U.S. patent application number 11/199617 was filed with the patent office on 2005-12-29 for tubular connection with slotted threads.
Invention is credited to Angelle, Jeremy R., Mosing, Donald E., Sipos, David L..
Application Number | 20050285399 11/199617 |
Document ID | / |
Family ID | 34521751 |
Filed Date | 2005-12-29 |
United States Patent
Application |
20050285399 |
Kind Code |
A1 |
Mosing, Donald E. ; et
al. |
December 29, 2005 |
Tubular connection with slotted threads
Abstract
A connection for the quick and functionally reliable connection
of tubulars including pipes and casing. The connection having a
male or pin end and a mating female, box, or socket end and
sections of circumferentially and axially extending protuberances
such as thread segments or lugs interrupted by slots extending
circumferentially and axially approximately the same distance as
the corresponding protuberance section and can have at least on
continuous, uninterrupted thread for a landing surface. Both the
pin and box have matching or corresponding arrays of interrupted
threads and slots. When properly aligned, the array will be
accepted by a corresponding slot when mating the pin and box. After
proper mating, the connection is secured by rotating the pin or box
to further mate the corresponding patches of the pin and box.
Inventors: |
Mosing, Donald E.;
(Lafayette, LA) ; Sipos, David L.; (Lafayette,
LA) ; Angelle, Jeremy R.; (Lafayette, LA) |
Correspondence
Address: |
THE MATTHEWS FIRM
2000 BERING DRIVE
SUITE 700
HOUSTON
TX
77057
US
|
Family ID: |
34521751 |
Appl. No.: |
11/199617 |
Filed: |
August 8, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11199617 |
Aug 8, 2005 |
|
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10690920 |
Oct 22, 2003 |
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Current U.S.
Class: |
285/391 |
Current CPC
Class: |
F16L 37/2445
20130101 |
Class at
Publication: |
285/391 |
International
Class: |
F16L 025/00 |
Claims
What is claimed is:
1. A connection for assembly of pipe, the connection comprising: a
first pipe having a female end; a second pipe having a male end;
said female end having an inner surface and an outer surface; said
male end having an inner surface and an outer surface; a first
plurality of protuberances circumferentially and longitudinally
spaced relative to each other about the inner surface of said
female end; a second plurality of protuberances circumferentially
and longitudinally spaced relative to each other about the outer
surface of said male end; wherein said circumferential spacing
forms a circumferential array comprising at least one longitudinal
column on both the inner surface of said female end and the outer
surface of said male end; said plurality of circumferential arrays
aligned such that said plurality of protuberances are accepted by a
mating pipe end when said male and female pipe ends move
longitudinally relative to each other for forming a connection; and
wherein the male and female ends engage upon any rotation of one
pipe relative to the other pipe wherein such rotation causes said
protuberances of the male end and said protuberances of the female
end to move circumferentially with respect to each other.
2. The connection according to claim 1, wherein said plurality of
arrays comprises an odd number of said arrays.
3. The connection according to claim 1, wherein at least some of
said protuberances are shaped to be radially captured to prevent
radial expansion of the female end relative to the male end.
4. The connection according to claim 1, wherein at least one of
said protuberances embodies at least one interference dimension
that causes one surface to displace a mating surface.
5. The connection of claim 1, wherein at least some of the
protuberances have a crest and a root and wherein radial
interference exists between the crest and root of at least one
mating protuberance, said interference increasing with the relative
rotation between the male and female ends.
6. The connection according to claim 1, wherein one wrap of said at
least one screw thread on at least one of said first and second
pipe ends is not interrupted by said slots, to provide a landing
surface for said pipe ends when they are moved longitudinally into
engagement.
7. The connection according to claim 1, further comprising a first
alignment indicator on said male end and a second alignment
indicator on said female end wherein said indicators being
positioned to correspond with the circumferential point that marks
the start of an array of protuberances such that when said
indicators are aligned prior to said rotation of one pipe relative
to the other pipe, said indicators will provide visual indication
of the amount of rotation.
8. The connection according to claim 1, wherein a locking element
preventing loosening extends through a wall of the female end to
project into the path at least one protuberance would traverse if
the connection were to loosen.
9. A method of making a connection comprising: providing a first
pipe having at least one female end, said female end having an
inner surface and an outer surface; providing a second pipe having
a at least one male end, said male end having an inner surface and
an outer surface; providing a first plurality of protuberances
circumferentially and longitudinally spaced relative to each other
about the inner surface of said female end; providing a second
plurality of protuberances circumferentially and longitudinally
spaced relative to each other about the outer surface of said male
end; wherein said circumferential spacing forms a circumferential
array comprising at least one longitudinal column on both the inner
surface of said female end and the outer surface of said male end;
aligning said first pipe and said second pipe such that the female
end of said first pipe is aligned to receive the male end of said
second pipe; further aligning said first pipe and said second pipe
wherein said plurality of circumferential arrays are aligned such
that said first plurality of protuberances, are accepted by a
mating pipe end when the pipe ends move longitudinally relative to
each other for forming a connection; providing longitudinal
movement wherein said male end will enter and mate with said female
end; continuing longitudinal movement until said male end is fully
engaged in said female end; and rotating one pipe with respect to
the other pipe wherein said rotation causes the protuberances of
the male and female ends to move circumferentially with respect to
each other and wherein the male and female ends engage each
other.
10. The method of claim 9, wherein the rotation of one pipe segment
with respect to the other pipe segment is less than 20 degrees.
11. The method of claim 9, further comprising the steps of
providing a first alignment indicator on said male end and a second
alignment indicator on said female end wherein said indicators
being positioned to correspond with the circumferential point that
marks the start of the circumferential array of protuberances such
that when said indicators are aligned prior to said rotation of one
pipe relative to the other pipe, said indicators will provide
visual indication of the amount of rotation.
12. A threaded connection for end-to-end assembly of pipe sections
to pipe strings, the connection comprising: a first pipe end with a
socket and a second pipe end with a pin to mate with said socket; a
plurality of first cam patches of first arcuate cams extending
peripherally about the inner surface of said socket, said first cam
patches separated by surfaces defining peripherally extending first
slots; a plurality of second cam patches of second arcuate cams
extending peripherally about the outer surface of said pin, said
second cam patches separated by surfaces defining peripherally
extending second slots; all said slots and patches arranged such
that said patches are accepted by said slots when said pin end is
axially inserted into said socket; all said arcuate cams axially
distributed some distance and comprising lands and grooves
peripherally extending some distance in a selected helical
direction, said grooves configured to accept said lands when
rotation of said box relative to said pin causes said lands to move
peripherally along said grooves; and at least one first abutting
surface on said first pipe arranged to oppose and mate with a
second abutting surface on said second pipe, with a selected axial
force, when said patches on said pin are approximately juxtaposed
with said patches on said socket.
13. The connection according to claim 12, wherein at least some of
said lands and their related said grooves are shaped to radially
capture said lands within its related said grooves to prevent
radial expansion of said socket relative to said pin.
14. The connection according to claim 12, wherein at least one of
said arcuate cams embodies at least one interference dimension that
causes one surface to displace a mating surface, by material
strain, to increase the torque required to rotate said first pipe
relative to said second pipe.
15. The connection according to claim 12, wherein one wrap of said
at least one screw thread on at least one of said first and second
pipe ends is not interrupted by said slots, to provide a landing
surface for said pipe ends when they are moved axially into
engagement.
16. The connection according to claim 12, wherein at least some of
said lands and grooves have dimensional relationships such that an
interference resists rotation of said socket relative to said pin,
said interference requiring expansion of said socket for the
connection to be completed.
17. The connection according to claim 12, wherein a locking element
extends through a wall of the socket to project into the path at
least one arcuate cam would traverse if the connection were to
loosen, to prevent such loosening.
18. A threaded connection for end-to-end assembly of pipe sections,
the connection comprising: first and second pipe ends to be
threadedly joined, said first pipe having female configuration
defined as a box, the second pipe having mating male configurations
defined as a pin; the box having, in series, a first abutment
surface defining one end of the first pipe, a first unthreaded
length, a first threaded length, a second unthreaded length, and a
second abutment surface to terminate the box configuration on the
first pipe; the pin having, in series, a third abutment surface to
mate said second abutment surface, a third unthreaded length to be
received in the second unthreaded length, a second threaded length
to mate with the first threaded length, a fourth unthreaded length
to be received in the first unthreaded length, and a fourth
abutment surface to mate with the first abutment surface and
terminate the pin configuration; the first and second threaded
lengths, each, comprising at least two patches of incomplete
threads on the pin and similar and mating patches of incomplete
threads in the box, all said patches formed by peripheral thread
cut-outs producing surfaces to define slots which will accept the
patches when the box receives the pin in axial relative movement,
the patches on the pin arranged to engage the patches in the box
when the pin is rotated relative to the box, said abutting surfaces
to be axially force loaded a preselected amount when the patches on
the pin are approximately juxtaposed with the patches on the
box.
19. The threaded connection of claim 18, wherein radial
interference exists between the crest and root of at least one
mating thread, said interference increasing, within selected
limits, with the relative tightening rotation between the pin and
the box.
20. The threaded connection of claim 19, wherein said interference
increases until a selected amount of relative rotation of the box
and pin is achieved, then said interference is reduced for the
remaining amount of the tightening relative rotation.
Description
RELATED APPLICATION
[0001] This application is a divisional application of U.S. patent
application Ser. No. 10/690,920, filed Oct. 22, 2003, entitled
"Tubular Connection with Slotted Threads."
FIELD OF THE INVENTION
[0002] The present invention relates generally to assembling pipe
sections together to produce, among other things, a pipe string
and, more particularly, to assembling pipe strings by use of
interrupted or slotted threads by which small partial turns of one
pipe portion relative to the other completes the individual
connection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a side elevation, partial cut away of a pin and
box connector.
[0004] FIG. 2 is an end view of FIG. 1, viewed from below.
[0005] FIG. 3 is a side view cut-away of a box and pin connector
illustrating taper threads.
[0006] FIG. 4 is similar to FIG. 3 but illustrating straight
threads.
[0007] FIG. 5 is a side view cut-away of another embodiment of the
present device.
[0008] FIG. 6 is a sectional view of one wall of a connector
illustrating an entrapment thread profile.
[0009] FIG. 7 is similar to FIG. 6 but illustrating another
embodiment of the present device.
[0010] FIG. 8 illustrates another embodiment of the present
device.
[0011] FIG. 9 illustrates another embodiment of the present
device.
[0012] FIG. 10 illustrates another embodiment of the present
device.
[0013] FIG. 11 represents a 180 degree plan view of a section of an
embodiment of the pipe connection.
[0014] FIG. 12 is a sectional view taken along line 12-12.
[0015] FIG. 13 is a sectional view taken along line 13-13.
[0016] FIG. 14 is a sectional view taken along line 14-14.
[0017] FIG. 15 represents a 180 degree plan view of a section of an
embodiment of the pipe connection.
[0018] FIG. 16 is a sectional view taken along line 16-16.
[0019] FIG. 17 represents an unfolded plan view of one embodiment
of a pin and box aligned for mating.
[0020] FIG. 18 is a sectional view taken along line 18-18.
[0021] FIG. 19 is a sectional view taken along line 19-19.
[0022] FIG. 20 represents an unfolded plan view of another
embodiment of a mated pin and box connection.
[0023] FIG. 21 is a sectional view taken along line 21-21.
[0024] FIG. 22 is a partial sectional view illustrating a thread
segment in a slot.
[0025] FIG. 23 is a sectional view taken along line 23-23.
[0026] FIG. 24 is a partial sectional view of a non-interfering
thread segment in a mating groove.
[0027] FIG. 25 is a sectional view taken along line 25-25.
[0028] FIG. 26 is a partial sectional view illustrating the use of
a set screw to prevent rotation.
[0029] FIG. 27 is a partial sectional view illustrating the
interference of the mating crest and root.
[0030] FIG. 28 is a side view cut away of a connector with buttress
threads.
[0031] FIGS. 29 and 30 are profiles of one form of buttress thread
for connectors.
[0032] FIG. 31 is a side view cut-away of a connector using wedge
threads.
[0033] FIG. 32 is a sectional view of a selected area illustrating
seals uncompressed.
[0034] FIG. 33 is similar to FIG. 32, with the seal more
compressed.
[0035] FIG. 34 is similar to FIG. 32, with the seal fully
compressed.
[0036] FIG. 35 is a side view of a pin end with spiral slots.
[0037] FIG. 36 is a side view of a box, cut away along the
centerline, with spiral slots.
[0038] FIG. 37 is an end view, from below, of FIG. 35.
[0039] FIG. 38 illustrates the present connection with a drive
shoe.
[0040] FIG. 39 illustrates a partially cut away view of a
coupling.
[0041] While the present invention will be described in connection
with presently contemplated embodiments, it will be understood that
it is not intended to limit the invention to those embodiments.
Further it should be understood that the drawings used to
illustrate these embodiments are also not intended to limit the
present invention but are intended to disclose the presently
contemplated embodiments. These descriptions and drawings are
intended to cover all alternatives, modifications, and equivalents
included within the spirit of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0042] The connections to be described herein may be produced in
the ends of pipe segments which are preferably but not exclusively
installed in a pipe string or can be produced as a short ring, or
length of pipe which is then attached to the pipe segment
preferably but not exclusively by welding.
[0043] The interrupted threads to be described herein can be
produced by removing sections of threads on a threaded connection
or can be produced by machining, milling, or a similar process. It
should be appreciated that the protuberances or thread segments, or
shorter pieces of the original thread that remain after a portion
of the threads are cut away or that are otherwise produced in or on
the pipe ends or attachable pipe segments are referred to as
interrupted threads, partial threads, lugs, cams, threads,
protrusions, protuberances, thread segments and the like. These
terms should not be distinguished based on method of production. As
an example, whether a protuberance is produced as a result of
removing a portion of an existing thread or by machining or milling
operations when no thread exists, the protuberance (or multiple
protuberances) would be within the scope of this invention
regardless of the term describing it. It should be further
appreciated that there are a large variety of synonyms for these
protuberances and the arrays of the protuberances that are formed
by cutting away sections of the threads or that are otherwise
produced in or on the pipe ends or attachable pipe segments.
Substantially the same synonyms are used when these protuberances
or thread segments are the result of machining, milling, or similar
operations to produce the pipe end configurations. The grouping of
these protuberances is typically referred to as arrays,
circumferential arrays, patches, cam patches and the like. The
areas between the arrays of protuberances are typically referred to
as slots or other synonymous names. These terms are used
interchangeably herein to aid those in the art with a more complete
understanding of the present invention. Thus, the name applied to
these protuberances, arrays of protuberances, or areas between the
arrays is not intended to limit the present invention.
[0044] FIGS. 1, 2, and 3 relate to embodiments of the connection
form. Pipe section 1 is joined to pipe section 2. FIGS. 1-5 define
the general areas of the connection rather than individual
features. The pin end has an array of interrupted threads or
protuberances CP between slots S. In one embodiment, slot S is a
circumferential cut-out that just removes the threads on three
places on the pin circumference. Similar cut-outs are made in the
box threads. The slots on each part will accept, in axial movement,
the thread segment arrays on the other part. The thread element TH
extending circumferentially across an array is the protuberance
which can be a partial thread, an interrupted thread, a thread
segment, a cam, a lug or a similar protrusion. When the parts move
axially together for pipe string assembly, abutment BA will be in
contact with the pin and abutment PA will be in contact with the
box. It should be appreciated that the terms pin and box refer to a
male end connection and female or socket end connection
respectively. When threads are dynamically loaded by pile driving,
the stab flank gets loaded by shock. Therefore, the stab flank is
sometimes referred to as the shock flank. Connecting configurations
that have sufficient shoulder, or abutment, area may not shock load
the threads.
[0045] Pipe segments subject to pile driving have a diameter to
wall thickness ratio that varies considerably. Different ratios
require different threads. Some ratios require abutments capable of
accepting pile driving loads borne by the abutments alone, with
threads accepting the rebound energy. In some cases threads alone
carry the shock load and no separate abutment is involved.
[0046] FIG. 3 shows box end 2a and pin end 1a with box extension BE
and pin extension PE separated by mating thread length MT. The
thread length is slightly tapered and the box and pin extensions
are cylindrical.
[0047] In FIG. 4, another embodiment, the threaded length MT is
generally straight and the extensions are generally conical.
Considering the connection as a box and pin arrangement, abutting
shoulders are preferably provided at each end of the threaded
engagement portion. In effect the threads or protrusions, pull the
shoulders into abutment. The preferred abutments are shaped to
prevent the radial separation that axial impacts tend to cause.
Both straight and tapered threads are disclosed with the present
novel features. Thread forms preferred are square, buttress, and
entrapment with the choice influenced by factors including pipe
wall thickness and the ratio of diameter to wall thickness of the
pipe. The abutments BA and PA have different amounts of taper. As
an option, either or both of the extensions can have interference
fits to seal the bore or to provide rotational restraint to prevent
unscrewing the connection when the hammering takes place. The
extensions shown, if tapered as shown, are tighter under hammer
blows that typically loosen the load flank of the thread segments.
It should be noted that the shock load on the abutments cause the
thinner pipe mating part to be thrust toward the nearest radially
restraining surface. It should be understood that pipe ends 1b and
2b may be rings to be welded to other pipe segments.
[0048] FIG. 5 is very much like FIG. 4 but the radial restraint
configurations of the abutments BA1 and PA1 have different
entrapment configurations. Likewise, pipe ends 1c and 2c may be
short rings to be attached later to the ends of pipe sections.
Extensions BE1 and PE1 may be straight as shown or tapered as in
FIG. 4.
[0049] When threads are used with thin walled pipe, the hammering
effect on the pipe wall near the connection shoulders can deform
the material radially. The result is generally failure. The threads
can be shaped to radially urge mating parts together. Such thread
sections are called capture or entrapment threads. The thread
section is preferably a dove tailed shape. If less radial security
is required, only one flank can be shaped for the entrapment. FIG.
6 illustrates an embodiment with thread entrapment profiles 18 and
19, useful for piping connections for wall thicknesses within
certain ranges. The illustration here shows an optional hook
pattern used on one flank. Thinner wall piping may require a hook
profile on both flanks. It should also be appreciated that other
forms of entrapment threads can also be utilized.
[0050] An embodiment of the present disclosure involves a coupling
that usually has unthreaded axial extensions, extending in both
axial directions from the threaded length, useful for alignment and
sealing. Those continuing surfaces may be cylindrical or conical,
or a combination of both when used with straight or tapered
threads. FIGS. 7-10 illustrate various embodiments of the present
device and illustrate sections through one wall of a pipe segment
joined by different configurations typically selected for certain
pipe wall thicknesses. It should be understood that while only
simple thread forms are illustrated, a variety of thread forms and
combinations could be used.
[0051] FIG. 7 illustrates an embodiment with a pin and box wall
joined with mating cylindrical surfaces 22a and mating cylindrical
surfaces 22b on opposite axial sides of mated interrupted thread
arrays. Female thread segments fc1-fc4 mate with male thread
segments mc1-mc4. A section cut through the center of any one of a
plurality of arrays would be identical. With the configuration
shown, surface 22a extends generally from the root dimension of the
pin thread and surface 22b extends generally from the root
dimension of the box thread. With this configuration, the slots do
not have to extend into surfaces 22a or surfaces 22b. The conical
abutments 20 and 21 plus conical abutments 23 and 24 often suffice
for shock loads of pile driving without the need for entrapment
thread forms. The thread arrays usually have a slight conical form
with the crest diameters typically increasing, between the lands,
towards the nose of the box.
[0052] FIG. 8 illustrates an embodiment of the connection with only
one driving abutment pair of mated surfaces similar to surfaces 23
and 24. Arrays on length 26 have substantial taper and mating
conical surfaces 25 can have substantial interference for
rotational security to prevent loosening by pile driving shock.
Interferences of surfaces on length 26 are increased by axial
compression due to driving shock. Gap 34 does not need to close and
resilient seals may or may not be required depending on the
application the device is utilized in.
[0053] FIG. 9 is quite similar to FIG. 7 but illustrates an
embodiment with the slot 28 on the pin and the array 29 on the box.
Axial relative movement can be almost complete before the relative
rotation of final joining takes place. Either or both mating
surfaces 33a and 33b can be somewhat conical and either or both may
carry seals such as 30 of the embodiment illustrated in FIG.
10.
[0054] FIG. 10 illustrates an alternate form of abutment, 31 and
32, that radially secures one abutting surface to the other to keep
the pipe segment from radially over-expanding at the ends during
driving. Seal 30 is typically not necessary but some companies
routinely require them.
[0055] FIG. 11 is a 180 degree plan view of an embodiment of a
mated pin and box connection. This illustrates a six phase pipe
connection using lugs or partial thread segments not produced by
threads. To wedge the threads together for maintaining tightness,
each partial thread can be independently shaped or all of them can
be collectively shaped by a parent thread cut in a long wedge shape
as illustrated in FIG. 31. The helical angle of the stab flank
differs from the helical angle of the load flank. Such partial
threads can also utilize the entrapment forms defined above. Pin
threads P and box threads B, move in the direction of the arrow for
tightening. The interrupted threads or protuberances are wedge
shaped, the angle being exaggerated, to pinch all flanks as
tightening proceeds. Pin 40 is drawn into box 41 by tightening of
the connection. The load flanks of thread segments B and P are
sloped to provide the specified compression with the amount of
relative rotation that brings the thread arrays into maximum
engagement. The stab flanks of the threads are sloped to achieve
rated torque when the thread arrays are in maximum engagement. This
arrangement can be used with any thread segment section profile and
the wedging action improves the function of entrapment profiles on
the thread segments. When thread segments, not produced by cutting
away threaded sections, are used the total effect of the described
wedge made of one long thread can be achieved on each short thread
segment. The wedging effect, is then achieved in only a fraction of
one turn. In such an embodiment, all thread segments can be alike
and equally strong. FIGS. 12-14 illustrate the relationships of
features of FIG. 11 at three section stations.
[0056] FIGS. 15 and 16 illustrate an embodiment having a high load
bearing surface arrangement. FIG. 15 illustrates an 180 degree plan
view of a mated pin and box connection. Box 51 has thread segments
52 in six equally spaced arrays (three shown) separated by six
slots. Pin 50 has thread segments 53 which mate with thread
segments 52. This design provides high load bearing area on mating
surfaces. It should be understood that although the thread segments
are illustrated with one particular thread form other forms can be
used. Masses 56a and 57a increase the load bearing material between
slots. Surfaces 56b and 57b are slot bottom related.
[0057] FIGS. 17, 18, and 19 illustrate features of an embodiment on
a separated connector with pin 60 and box 61 aligned for axial
movement as indicated by arrow 68 to move the thread arrays 62 into
slots 61a. The same movement moves thread segments 66 into slots
60a. To avoid confusion of dotted lines, box end 61 is shown as
transparent. All thread segments illustrated were generated as
threads with a helix angle typified by line 69. Helical partial or
interrupted threads can be provided either by threading or by
repeating any one thread segment in each of the remaining arrays of
threads. It should be understood that any one axial level of repeat
partial threads will start at the same axial location in each array
of threads. By contrast, thread-cut interrupted threads will
advance axially an amount of the thread pitch, divided by the
number of cut-outs. Thread cut arrays suggest that the pin be
inserted into the box at only one circumferentially related
location. All threads are limited to the length bounded by lines 64
and 65. Thread roots 63 and 67 can be sized to provide a
substantially tight fit or even some interference with the crests
of the mating thread segments. The strain is minor but it provides
a brake effect to stabilize threads subject to shock loading. Any
thread flank can be used. If wedge threads of a long taper type are
used (note FIG. 31) the thread lands are narrow at the nose end of
both components. The narrow lands start in wide grooves and the
difference diminishes as the connection is made up.
[0058] With interrupted threads, the entire make-up can take a
relatively small fraction of a full rotation of the pipe. The
number of circumferential arrays of the protuberances or
interrupted threads determine the required amount of turn of the
male end or pin relative to the female end or box to make the
connection. The array is that circumferential area of thread that
was not cut away or of the machined protuberances or lugs. With
four cut-outs, a thread would produce four thread segments (also
referred to as lugs, protuberances, protrusions, and the like) per
turn and advance axially one-fourth of the thread pitch. In an
embodiment of the present device the entire make-up, of the
connection, is achieved in as little as one-twentieth ({fraction
(1/20)}) of a turn and the wedging effect is the same as for long
continuous threads. This is a factor of the number of arrays and
slots. However, more thread length may be required, to maintain
joint strength, because of the amount of threads which are cut away
as slots. But the small turn requirement, such as only
one-twentieth of a full turn, still remains valid. The additional
thread length is gained by having more thread segments in the axial
array.
[0059] FIGS. 20 and 21 illustrate a particular feature of an
embodiment but they are otherwise much the same as FIGS. 17, 18,
and 19. This is an interrupted thread concept with all wraps of
thread cut by slots except the last turn 74 on pin 70. An
interrupted thread array is comprised of thread segments 72 which
are separated by grooves 73. Slots 75 are of different length
because they extend to but do not cut thread wrap 74. The uncut
thread provides a landing flank for the thread segments of the
mating box 71. When the most distal box threads engage the uncut
thread, a box thread will be aligned, for instance, with groove 73.
This avoids damage to the driving abutments on the mating parts.
Area 76 adjoins a flank that is not loaded.
[0060] If preferred, the pin 70 can be oriented such that an array
will enter a slot counterclockwise of the slot normally entered.
The uncut thread 74 will allow the mating parts to turn the arrays
through a slot before entering the target array that pulls the
abutting surfaces into final position.
[0061] The thread angle can be increased by using double, or
multiple, threads in which case more than one thread starts at the
same axial position. Thus, if a faster helical angle is needed, an
embodiment with multiple threads can be used. More than one thread
would start at a selected transverse plane. The resulting plurality
of threads would each progress axially a greater amount per turn.
If using thread segments not derived from threads, the helical
angle can have any practical rate of axial advance relative to
circumferential extension.
[0062] FIGS. 22-27 pertain to an embodiment with thread
configurations similar to most disclosed coupling arrangements.
However, these configurations are distinguishable in that the
configuration are comprised of thread segments or protuberances
instead of the common uninterrupted or continuous thread. To secure
the connection to prevent unscrewing threads when hammering the
assembly into the earth, optional thread security arrangements can
be provided. These arrangements can be applied separately to a
particular embodiment or can be combined together on one
embodiment. One such action is a tighter fit, including a slight
interference between the root and crest of mating partial threads
or lugs, between mating elements as tightening rotation occurs.
Radial strain which can be caused by an extremely tight fit and
which is well within the elastic limit of the material, provides a
reversibility of the connection process with externally provided
torque. Another such action is provided in the form of a blocking
element, preferably a set screw that extends through the wall of
the box and into the path that would be traversed by a thread
segment if the connection rotates in a direction to loosen the
connection. It should be appreciated that the set screw can be used
with most embodiments and does not require a particular
protuberance shape or any particular type of thread segment.
Protuberance 80 on part 83 enters slot 81 on mating part 82 with
some clearance between all opposed surfaces. When axial aligned,
rotation of part 82 brings thread segment 84 on part 82 into
juxtaposition with thread segment 80 on part 83. In this case there
are no radial loads between thread crests and opposing thread
roots. The embodiment illustrated in FIG. 25 does not show load
flanks in contact but that condition will exist during the diving
operation.
[0063] FIG. 26 illustrates the use of a set screw 85a to prevent
rotation in a direction for loosening the connection. The set screw
85a extends though the wall of part 85 into slot 81 thereby
preventing any movement of thread segment 86 in a direction toward
the set screw 85a.
[0064] FIG. 27 illustrates a thread form embodiment wherein there
is some interference between the thread segment 86 and the mating
body 85. Here the thread roots are sized to interfere with the
crests of the mating thread. It should be appreciated that any
interference between the crests, of one part, and the roots of the
mating part must be sufficiently minor as to be able to accommodate
any deflection and/or deformation within the plastic deformation
zone of the threads. It should further be understood that such
interference and subsequent plastic deformation can be useful in
handling large diameter pipe. Such sizes sometimes lose their
cylindricity and the deformation, caused by interfering thread
elements as described herein, can help the ends maintain a
cylindrical cross-section and thus allow for easier mating of the
box and pin ends.
[0065] FIGS. 28, 29, and 30 illustrate embodiments with a modified
wedge thread format that does not depend upon a shoulder-type
abutment. The tapered threads provide the torque stop. The threads
on FIGS. 28 and 29 are shaped with radii 98a and 98b on the crests
and roots and load flanks 97b and stab flanks 97a have different
angular relationships to the pipe axis. In this thread format the
stab flanks are also shock flanks during pile driving. The male and
female profiles are the same. FIG. 30 illustrates thread crests 99c
and 99d flattened and, hence, are a more economical arrangement.
The angles of flanks 99a and 99b remain unchanged. It should be
understood that the angles shown are illustrative and are not to be
construed as limitations.
[0066] In FIG. 28, threads 96a are cut away in the slot areas 95
only enough, for axial passage of the arrays into the slots.
Although shown as an interrupted thread, the arrays can be
identical and made up of non-thread protuberances as described
herein. Fluid seals can be achieved by mating conical surfaces in
unthreaded and unslotted areas. An optional resilient seal is shown
as s.
[0067] FIG. 31 illustrates an embodiment with a connection similar
to that of FIG. 28 but the threads are wedge threads. The long
wedge shape brings all thread surfaces into contact on both the
stab and load flanks when the connection is torqued together. The
entering end of the pin thread is axially narrow and widens and the
entering groove on the box is wide and narrows. Such a design is
accomplished during the manufacturing stage by making a tight
connection, marking the pipe, disconnecting the assembly, and
milling the appropriate slot to produce the interrupted threads.
When the interrupted threads are again connected, the individual
thread segments will wedge or jam, in a partial tightening turn, as
they did before cutting/milling the slots. Two shoulders are shown
to be abutting but either or both can be gaps. Pin 93 has threads
93a that start axially narrow at the nose and broaden with each
turn. Box 92 has threads 92a that are axially narrow at the start
at the nose and widen as the thread progresses axially. By way of
explanation, the center of the crest describes a helical line but
the flanks progress axially at different helical angles. The crests
and root can be made to clear or fit tightly as demanded by the
planned operation of the tool. This format can seal by conical
surface interference on other than thread areas. An alternate
resilient seal is shown as s.
[0068] FIGS. 32-34 illustrate embodiments with optional methods for
sealing a box nose with an abutment surface that is angled to
radially capture the end of the nose. Radius R1 and radius R2 are
such that, when they intersect, they will capture and squeeze seal
100. Pin end 71 has conical surface 71 a that engages a mating
surface 70b on box end 70 when the connection is made up. The
capture angle squeezes the tubular nose radially inward, closing
the gap 70a. A redundant, or alternate, seal ring 102, in groove
101, also seals the connection. When gap 70a closes, the seals are
capable of closure against very high pressure. Either, neither, or
both of the seals shown may be used with connections disclosed
herein.
[0069] FIGS. 35-37 illustrate embodiments with spiral slots
separating the interrupted thread arrays that extend in a helical
direction. Pipe end 100 has a spiral slot 100c separating arrays
100a and 100b. Pipe end 101 has a spiral slot 101c separating
arrays 101a and 101b. FIG. 37 illustrates quarter cut slots which
require one quarter turn to bring the arrays into full
engagement.
[0070] As illustrated in FIG. 39 an embodiment of the present
device can have a drive shoe (710) connected to the bottom of the
pipe string (720). The drive shoe (710) can be attached to the
lowermost pipe by welding, by a threaded connection, or even with
the interrupted thread connection. FIG. 38 illustrates yet another
embodiment of the present device in the form of a coupling which
can also be used, among other things, to connect the drive shoe to
the lowermost pipe. The coupling may connect to the upper end of
the drive shoe. This connection would preferably be a welded or
threaded connection. However, it should be appreciated that the
drive shoe and the coupling could also be connected by a variety of
methods. The coupling end furthest from the drive shoe,
longitudinally, would then have the interrupted thread
connection.
[0071] The coupling illustrated in FIG. 38 is shown with the
interrupted thread connection on both ends. However, it should be
appreciated that this coupling could have embodiments with any
combination of male and female ends including but not limited to a
threaded male end and an interrupted thread female end, a threaded
female end and an interrupted thread male end, an interrupted
thread female end and an interrupted thread female end, an
interrupted thread male end and an interrupted thread male end, an
interrupted thread female end and an interrupted thread male end,
an interrupted thread male end and a female weld end, a male weld
end and an interrupted thread female end, and the like.
[0072] The use of a coupling is also advantageous to adapt an
existing inventory of pipe which may have already been manufactured
to be threaded or welded. In such a case, the coupling could be
easily attached to the pipes prior to the delivery of the pipes to
the rig, or in an area adjacent to the rig. This method would allow
the conversion of such inventory pipe to pipe with the interrupted
or slotted thread connection. In order to be able to utilize the
majority of the inventory pipe, the coupling would need to be
produced with the variety of ends described herein. Thus, a
connection could be adapted to fit substantially all pipe
including, but not limited to pipes with threaded ends, weld ends,
pipes which need to be run pin up, pipes which need to be run pin
down, pipes that for any reason already have some other type of end
connection and the like.
[0073] In use, the pipe ends are preferably produced prior to the
pipe being shipped to the drilling rig. Or as described herein, the
ends can be attached to the pipes near the rig or couplings could
be used and attached to the pipes before shipment to the rig or
near the rig. In any case, an objective would be for the pipe ends
to be prepared with the interrupted thread or slotted thread ends
prior to the time the pipes are needed for driving a pipe string
into the ground. Preferably, once the first pipe is substantially
in a position requiring the attachment of the next length of pipe,
a second pipe is preferably positioned such that the male or pin
end of the second pipe is substantially longitudinally aligned with
the female or box end of the first pipe. It should be appreciated
that if the first pipe has a male end or the pin up then the second
pipe must be aligned with the female end or box down. An
alternative would be to use a coupling with an end connection
selected for the desired mating connections. Preferably, after the
first and second pipes are substantially aligned longitudinally,
they are preferably aligned such that the arrays of protuberances
of one pipe end substantially align with the slots of the other
mating pipe end. This alignment can be preferably accomplished by
rotation of one of the pipes with respect to the other. Next,
preferably the second pipe is moved substantially in a longitudinal
direction with respect to the first pipe. When the pipes have
substantially fully mated in the longitudinal direction, one pipe
is rotated with respect to the other pipe. With any rotation of the
one pipe, the connection is complete. The amount of rotation
preferably depends on the number of arrays of protuberances and the
number of protuberances in each longitudinal column.
[0074] From the foregoing, it can be seen that this invention is
one well adapted to meet the needs of industry. It will be
understood that certain features and sub-combinations are of
utility and may be employed without reference to other features and
sub-combinations. This is contemplated by and is within the scope
of the claims.
[0075] As many possible embodiments may be made of the connector of
this invention without departing from the scope thereof, it is to
be understood that all matter herein set forth or shown in the
accompanying drawings is to be interpreted as illustrative and not
in a limiting sense. The foregoing disclosure and description of
the invention is illustrative and explanatory thereof, and it will
be appreciated by those skilled in the art, that various changes in
the size, shape and materials, the use of mechanical equivalents,
as well as in the details of the illustrated construction or
combinations of features of the various coring elements may be made
without departing from the spirit of the invention. The graphic
preference for axially directed slots is not to be construed as a
limitation.
* * * * *